pubmed.ncbi.nlm.nih.gov

Antisense Oligonucleotide Therapy for the Nervous System: From Bench to Bedside with Emphasis on Pediatric Neurology - PubMed

  • ️Sat Jan 01 2022

Review

Antisense Oligonucleotide Therapy for the Nervous System: From Bench to Bedside with Emphasis on Pediatric Neurology

Man Amanat et al. Pharmaceutics. 2022.

Abstract

Antisense oligonucleotides (ASOs) are disease-modifying agents affecting protein-coding and noncoding ribonucleic acids. Depending on the chemical modification and the location of hybridization, ASOs are able to reduce the level of toxic proteins, increase the level of functional protein, or modify the structure of impaired protein to improve function. There are multiple challenges in delivering ASOs to their site of action. Chemical modifications in the phosphodiester bond, nucleotide sugar, and nucleobase can increase structural thermodynamic stability and prevent ASO degradation. Furthermore, different particles, including viral vectors, conjugated peptides, conjugated antibodies, and nanocarriers, may improve ASO delivery. To date, six ASOs have been approved by the US Food and Drug Administration (FDA) in three neurological disorders: spinal muscular atrophy, Duchenne muscular dystrophy, and polyneuropathy caused by hereditary transthyretin amyloidosis. Ongoing preclinical and clinical studies are assessing the safety and efficacy of ASOs in multiple genetic and acquired neurological conditions. The current review provides an update on underlying mechanisms, design, chemical modifications, and delivery of ASOs. The administration of FDA-approved ASOs in neurological disorders is described, and current evidence on the safety and efficacy of ASOs in other neurological conditions, including pediatric neurological disorders, is reviewed.

Keywords: Alexander disease; Angelman syndrome; Canavan disease; Duchenne muscular dystrophy; Pelizaeus–Merzbacher disease; RNA therapy; antisense oligonucleotide; multiple sclerosis; spinal muscular atrophy; transthyretin amyloidosis.

PubMed Disclaimer

Conflict of interest statement

A.F. consults for Poxel, Calico Therapeutics, Autobahn Therapeutics, Affinia Therapeutics, Minoryx Therapeutics, SwanBio Therapeutics, and Dicerna and receives research support as institutional investigator for clinical trials from Minoryx and Viking Therapeutics. A.F. is also coinventor of a patent licensed to Ashvattha Therapeutic. D.G.L has been site principal investigator for the golodirsen and casimersen clinical trials.

Figures

Figure 1
Figure 1

(A) Aptamers consist of 3D-folded single-stranded oligonucleotides with the ability to bind to proteins and peptides. They can inhibit the function of target proteins and peptides. (B) RNA interference (RNAi) oligonucleotides are double-stranded RNAs and include small interfering RNAs (siRNAs) and small hairpin RNAs (shRNAs). Dicer enzyme cleaves double-stranded RNAi, and antisense (guide) strands degrade target mRNAs or arrest translational processes via an RNA-induced silencing complex (RISC). RISC is a multiprotein complex that alternates gene expression. The miRNAs or siRNAs are loaded on an RISC and attach to their complementary mRNA transcripts. An RISC-associated protein or Argonaute is then activated and inhibits protein synthesis by cleaving mRNA or arresting translational process. The siRNAs transport to cell cytoplasm and are associated with Dicer/RISC, but shRNAs initially transport to cell nuclei using a vector for transcription. The product will then export to cell cytoplasm and will be associated with Dicer/RISC. (C) Small activating RNAs (saRNAs) are double-stranded RNAs activating gene expression via an RISC. The saRNAs are loaded on RISC and bind to chemical tags or RNA copies attached to DNA that prevent promoter activation. Argonaute is then activated and increases gene expression by removing these chemical tags and RNA copies. (D) Antisense oligonucleotides (ASOs) modify gene expression by binding to mRNA or noncoding RNA (miRNA). “Schematic diagram created with premade icons and templates from biorender.com (accessed on 20 August 2022)”.

Figure 2
Figure 2

Antisense oligonucleotides (ASOs) can bind to mRNA and reduce the levels of toxic protein by (A) translational arrest due to the steric hindrance of ribosomal subunit binding, (B) inducing the RNase H1 endonuclease activity that cleaves RNA-DNA hybrids on mRNA, or (C) destabilizing pre-mRNA by inhibiting 5′ cap formation/modulating 3′ polyadenylation. (D) ASOs are able to increase gene expression by targeting upstream open reading frames within the 5′ untranslated region or nonproductive alternative splicing. (E) ASOs can modify mRNA splicing by targeting splicing enhancers/splicing silencers or inducing splicing enhancer by including a noncomplementary tail and alternate nonfunctional protein to improve function. (F) ASOs can target miRNAs and inhibit their RISC-dependent action to reduce protein translation. (G) Other noncoding RNAs can be the target of ASOs. ASOs targeting a noncoding transcript (UBE3A-ATS) were shown to activate paternal UBE3A gene expression in Angelman syndrome. “Schematic diagram created with premade icons and templates from biorender.com (accessed on 20 August 2022)”.

Figure 3
Figure 3

Antisense oligonucleotide modifications include modified phosphodiester bond (e.g., phosphorothioate, boranophosphate, methylphosphonate, phosphoramidite, and p-ethoxy), modified 2′ nucleotide sugar (e.g., 2′-O-methyl (2′-O-Me), 2′-O-methoxyethyl (2′-O-MOE), locked nucleic acid (LNA), constrained ethyl (cEt), and 2′-fluoro (2′ F)), modified phosphodiester bond and five-carbon sugar (e.g., phosphorodiamidate morpholino oligomer (PMO) and peptide nucleic acid (PNA)) and modified nucleobase (e.g., 5-methyl cytosine and G-clamp). “Schematic diagram created with premade icons and templates from biorender.com (accessed on 20 August 2022)”.

Figure 4
Figure 4

Antisense oligonucleotides can be delivered into the cells more efficiently using (A) viral vectors, (B) conjugated peptides, antibodies, and other ligands (e.g., aptamers and acetylgalactosamine (GaINAc)), (C) nanoparticles, or (D) extracellular vesicles. “Schematic diagram created with premade icons and templates from biorender.com (accessed on 20 August 2022)”.

Figure 5
Figure 5

(A) Membrane transduction is an energy-independent pathway to deliver cell-penetrating peptides (CPPs) and their cargo into the cells via the interaction between positively charged CPPs and negatively charged phospholipids of cell membrane. This interaction forms transient structures including pores, carpet-like structures caused by destabilizing cell membrane, or inverted micelles that facilitate delivery. (B) Endocytic internalization is an energy-dependent pathway and is mostly directed toward macropinocytosis, clathrin-mediated, caveolin-mediated, or clathrin/caveolin-independent (not shown in this figure) pathway. “Schematic diagram created with premade icons and templates from biorender.com (accessed on 20 August 2022)”.

Figure 6
Figure 6

Common routes of antisense oligonucleotide (ASO) administration in neurological disorders include (A) intravitreal, (B) intranasal, (C) subcutaneous, (D) intravenous, (E) intraventricular, and (F) intrathecal injections. Among FDA-approved ASOs, eteplirsen is injected using subcutaneous route; inotersen, golodirsen, viltolarsen, and casimersen are injected using the intravenous route; and nusinersen is injected using intrathecal route. The intravitreal route of ASO delivery is currently used for preclinical studies and clinical studies on neuro-ophthalmic conditions. The intraventricular and intranasal routes of ASO administration are currently in preclinical stages. “Schematic diagram created with premade icons and templates from biorender.com (accessed on 20 August 2022)”.

Similar articles

Cited by

References

    1. Gragoudas E.S., Adamis A.P., Cunningham E.T., Jr., Feinsod M., Guyer D.R. Pegaptanib for neovascular age-related macular degeneration. N. Engl. J. Med. 2004;351:2805–2816. doi: 10.1056/NEJMoa042760. - DOI - PubMed
    1. Adams D., Gonzalez-Duarte A., O’Riordan W.D., Yang C.C., Ueda M., Kristen A.V., Tournev I., Schmidt H.H., Coelho T., Berk J.L., et al. Patisiran, an RNAi therapeutic, for hereditary transthyretin amyloidosis. N. Engl. J. Med. 2018;379:11–21. doi: 10.1056/NEJMoa1716153. - DOI - PubMed
    1. Balwani M., Sardh E., Ventura P., Peiró P.A., Rees D.C., Stölzel U., Bissell D.M., Bonkovsky H.L., Windyga J., Anderson K.E., et al. Phase 3 trial of RNAi therapeutic givosiran for acute intermittent porphyria. N. Engl. J. Med. 2020;382:2289–2301. doi: 10.1056/NEJMoa1913147. - DOI - PubMed
    1. Askari F.K., McDonnell W.M. Antisense-oligonucleotide therapy. N. Engl. J. Med. 1996;334:316–318. doi: 10.1056/NEJM199602013340508. - DOI - PubMed
    1. Vitravene Study Group A randomized controlled clinical trial of intravitreous fomivirsen for treatment of newly diagnosed peripheral cytomegalovirus retinitis in patients with AIDS. Am. J. Ophthalmol. 2002;133:467–474. - PubMed

Publication types